> but does the collection methods work the same? Yes, more or less, they're the same. It's simple enough to restrict measurements to just surface observations

> but does the collection methods work the same? Yes, more or less, they're the same. It's simple enough to restrict measurements to just surface observations made with a thermometer of some sort if you want a wholly apples-to-apples, long-term temperature record. You don't have to add in satellite data (satellites don't directly retrieve surface air temperature so the direct comparison is fraught) although there do exist techniques which leverage it to augment the lack of spatial coverage of surface observations, especially over oceans. Quality issues have been studied ad nauseum over the past thirty years. Nearly half a dozen independent efforts have all tackled this problem. Probably the most notable recent one is the Berkeley Earth Land/Ocean Temperature Record (Rohde and Hausfather, 2020 -https://essd.copernicus.org/articles/12/3469/2020/essd-12-3469-2020.html https://essd.copernicus.org/articles/12/3469/2020/essd-12-34...).